Service Suspension on after 2 months of rear airshocks replaced

tomustang

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2008 Yukon Denali, Stock Suspension

I have replaced the rear air shocks which were blown out at the bottom with Arnott AS2708's back in May without issue. For a week now I've been getting the Service Suspension message off and on. When I look back at the air shocks I can see the bags aren't fully filled along with the strut shaft being visible.

Without a trailer on the rear of the yukon, it looks like the ride is at the highest setting, perhaps autoride is forcing it up but without the assistance of the airbags? When I'm driving about hitting bumps I can hear the top of the airbag housing hitting the bottom of the shock top. When I'm trailering the ride flattens out. At one time I was trailering I got the Service Message and noticed the bags wernt filling up, I climbed underneath and checked all the wire connections that I could, added dielectric grease, and giggled all the wires. I then started it up and the pump ran and the system leveled back out.

I heard the Arnotts were the best replacements out of the other options, but could there still be an issue with them not filling up or should I look into the autoleveling, or wiring?
 

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George B

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Your compressor is not keeping them inflated. Usually when the shocks go the compressor isn’t far behind. Do you hear it run when you first start the truck?.
Check fuses and the relay down under the master cylinder.
 

tomustang

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Your compressor is not keeping them inflated. Usually when the shocks go the compressor isn’t far behind. Do you hear it run when you first start the truck?.
Check fuses and the relay down under the master cylinder.
The pump has been replaced about 2 years ago when it was first showing signs it was going out (getting louder)

How the fuse/relay be bad if the pump still turns on?

Before I posted I did a quick turn on and the pump ran, threw on a trailer for weight and watched it drop down and stop at level but the pump didn't turn on.
 

tomustang

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Plugged in a scanner and got 2 codes:

C0585-04
Left rear actuator circuit open

C0660-06
Level control exhaust valve circuit short to ground/open
 

George B

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There is a good thread about this system here. The first code is likely a failed shock. The second is an issue with the vent valve on the pump. I have experienced the first and had it corrected under warranty by Arnott. I replaced my pump at the same time since it had also failed and the exhaust valve had failed.
 

tomustang

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There is a good thread about this system here. The first code is likely a failed shock. The second is an issue with the vent valve on the pump. I have experienced the first and had it corrected under warranty by Arnott. I replaced my pump at the same time since it had also failed and the exhaust valve had failed.
As for the comp vent valve, since the short to ground code is showing I'm assuming the actuator is inside or attached to the compressor? I'd test some wiring but I don't know which wires to test.

The first code could just be me fiddling around with the connections and seeing if everything's buttoned-up.

I have heard that the arnotts being the best but there were several times where people complained about them failing as well
 

George B

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When my new Arnott shock went bad I could clear that same code and it would come right back.
The vent valve is part of the compressor assembly. There is a TSB about pinched wires so you might take that compressor assembly out and give it a look over.
 

tomustang

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When my new Arnott shock went bad I could clear that same code and it would come right back.
The vent valve is part of the compressor assembly. There is a TSB about pinched wires so you might take that compressor assembly out and give it a look over.
Since the valve was in the compressor I ordered a new one. Came 1 day shipped with rockauto, I was impressed. Turns out the previous compressor I bought in 2017 has a lifetime warranty but they didn't have any stock so I have the option to get a refund out it.

The replacement fixed the problem.
 

George B

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I just had a line pop off on mine and deflate the system. Im 100 miles from home. Hope it stays on.
 

Joseph Garcia

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Since the valve was in the compressor I ordered a new one. Came 1 day shipped with rockauto, I was impressed. Turns out the previous compressor I bought in 2017 has a lifetime warranty but they didn't have any stock so I have the option to get a refund out it.

The replacement fixed the problem.
Thank you for closing the loop on your issue with this post on the solution. Much appreciated. Our collective knowledge base is increased.
 

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